PVC nanocomposites are prepared in suspension polymerization process in a typical equipment used for PVC production. The polymerization is carried out in the presence of spherical nanofillers e.g. nanosilica prepared in sol-gel process or hybrid silicone-acrylic core/shell filler. The nanofillers are added to the polymerization mixture in the amounts up to 1 wt. % per vinyl chloride monomer (VCM). These fillers do not disturb the polymerization process, do not prolong it and do not interact with initiators or other additives used in the process. The nanofillers used are dispersed in aqueous phase. Such dispersion can be stabilized with protective colloids. This form of a fillers prevents its agglomeration.

Advantages of the technology offered

Mechanical properties (impact strength, tensile strength) of the nanocomposites prepared by the method described are better than those of standard PVC prepared by standard suspension method. The nanofiller addition improves impact strength about 20–50 % dependently on the blend composition and does not influence the final product hardness.

Preparation of nanocomposites in the polymerization step is advantageous in comparison with applying of nanofillers in PVC processing as it gives excellent dispersions of the nanofillers in PVC grains and let use smaller amounts of them to reach the same properties improvements.

The process can be applied for the preparation of PVC nanocomposites of any molecular weight (full range of K value). Silica nanofiller allows controlling the polymer molecular weight in some range.

Equipment

The process can be used in every plant of VCM suspension polymerization. Any tank in the lines of media dosage to the polymerization reactor can be used as a nanofiller tank.

Patents

Polish patent application P-384 835 (2008) „Method of the suspension polymerization of vinyl chloride in the presence of a nanofiller”.

Polish patent application P-388 960 (2009) „Method of the suspension polymerization of vinyl chloride in the presence of a nanofiller”.

European patent application PCT/PL2009/000087 (2009) „Method for the suspension polymerization of vinyl chloride in the presence of a nanofiller”.

Market competitiveness

There is no PVC nanocomposites in the world market in spite of intensive works of many research centers, known from the published papers and patents. The only known to us trial of the production of such nanocomposite is introduction of the pilot plant for physical mixing of emulsion PVC latex and bentonite aqueous dispersion. The dried product is a blend called NanoVin®. Production in the industrial scale has not started yet.

References

PVC nanocomposites production (at reactor 1 m3 of capacity) in Spolana a.s. in Czech Republic (ANWIL SA Group) showed that suspension polymerization of VCM in the presence of spherical nanofillers is possible.